Summary of September 2017 Monthly Hydrologic Conditions
Compiled in cooperation with the New Jersey Department of Environmental Protection
Precipitation was below normal at the Newark and Trenton index stations, and above normal at the Atlantic City index station for the reference period 1981-2010. Newark reported 1.72 inches, which is 45.03 percent of normal. Atlantic City reported 4.05 inches, which is 128.57 percent of normal. Trenton reported 1.86 inches, which is 43.56 percent of normal. Total precipitation over the past 12 months was: 51.83 inches at Newark, which is 5.58 inches above normal; 50.05 inches at Atlantic City, which is 8.30 inches above normal; and 40.67 inches at Trenton, which is 5.77 inches below normal.
Combined storage in the thirteen major water supply reservoirs as of September 30 was 56.492 billion gallons (69.8 percent of capacity), which is greater than the average September contents for the reference period 1961-1990. The storage was 7.793 billion gallons less than one month ago and 13.040 billion gallons greater than one year ago. The thirteen major water supply reservoirs are as follows: Lake Tappan, Woodcliff Lake, Oradell Reservoir, DeForest Lake, Splitrock Reservoir, Boonton Reservoir, Canistear Reservoir, Oak Ridge Reservoir, Clinton Reservoir, Charlotteburg Reservoir, Echo Lake, Wanaque Reservoir and Spruce Run Reservoir.
Streamflow was below the long-term monthly-mean for the reference period 1981-2010 at all three index stations. The monthly-mean discharge at South Branch Raritan River near High Bridge was 36.8 ft3/s, 52.5 percent of the long-term mean. The monthly-mean discharge of the Great Egg Harbor River at Folsom was 41.2 ft3/s, 79.1 percent of the long-term mean. The monthly mean discharge of the Delaware River at Trenton was 4,870 ft3/s, 67.2 percent of the long-term mean. The observed daily mean discharge of the Delaware River at Trenton on September 30 was 3,490 ft3/s.
Groundwater levels, as measured in water-table observation wells for the month of September were below normal at the Morrell 1 and Vocational School 2 index wells, and were above normal at the Readington School 11 index well. Levels decreased from last month at all three index wells. Levels were higher than one year ago at the Readington School 11 and Morrell 1 index wells, and lower than one year ago at the Vocational School 2 index well.
Water-quality parameters collected from the Delaware River at Trenton were within the range of historical monthly values. Water temperature ranged from 18.3 to 26.3 degrees Celsius. Dissolved oxygen ranged from 7.6 to 10.3 milligrams per liter. Specific conductance ranged from 219 to 284 microsiemens per centimeter at 25°C.
Note: The preceding data is preliminary and subject to revision.
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